You don’t even know what the hell you’re talking about.
This is running in the cloud so how the hell is it running on your machine?
You will have to install a “Client”. That client will assume full remote control of your machine. While everyone is thinking browser it will actually be a direct client/server connection. It is the only way they can claim it as an “OS” and not just another browser linked to a webserver.
And they will be completely legal to do so because you will agree to give them this access through their crooked TOS contract when installing the client. This has been done before, think the first AOL but with more control and data transfer access over your machine in real time.
Curious why you are always so hot to defend the arrogant and extortive business model of the most crooked company in the world no matter what they do? Retired from MS? Work for MS? Own stock?